Orange County

Volunteers, state to fight invasive plants along the Eno by land and by sea

Mats of the non-native, invasive hydrilla is pictured in the Eno River downstream of Hillsborough.
Mats of the non-native, invasive hydrilla is pictured in the Eno River downstream of Hillsborough. Town of Hillsborough

Invasive plants are abundant in Hillsborough, but environmental officials and volunteers are fighting back by land and by sea.

Herbicide treatment for an infestation of the rapidly growing aquatic plant Hydrilla in the Eno River resumed May 24.

Hydrilla has a thin, long stem with small, serrated leaves growing along the length of the plant. Although it usually stays below water, in dense quantities it creates thick mats on the surface of waterways, impeding boating, fishing and swimming.

The plant, native to Asia, crowds out native vegetation as it grows and can harm fish and bird species. It can also clog intakes where rivers and reservoirs are used for drinking water supplies and irrigation.

Dense beds of Hydrilla can produce a toxin deadly to waterfowl. The plant is perennial, returning each summer. If left untreated, biologists say, Hydrilla could spread to Falls Lake.

A fluridone-based herbicide is being applied in a 22-mile target zone of Eno River from south of Lake Ben Johnston in Hillsborough to Roxboro Road in Durham County. It is being applied at a level that is safe for people and animals, according to the U.S. Environmental Protection Agency.

A 2-year pilot study in 2015 and 2016 showed a significant reduction in Hydrilla without impacts to the rest of the ecosystem or to human health.

“Fluridone is a fantastic chemical in that it only affects Hydrilla,” said Kimberly Radewicz, ranger at Eno River State Park. It has proved to be the best method to fight Hydrilla in the Eno River, she said.

The Eno River Hydrilla Management Task Force expanded the treatment area to just below Lake Ben Johnson Dam in 2017 and plan to apply the herbicide to the larger area this year. The treatment will continue through September, during which property owners should not use its water for irrigation.

Hydrilla was first discovered in the Eno River watershed in the early 1990s in Lake Orange, upstream of Hillsborough. Biologists confirmed its presence in the West Fork Reservoir in 2009. The N.C. Division of Water Resources is actively managing Hydrilla in both upstream reservoirs.

People can help stop the spread of Hydrilla by reporting sightings to Eno River State Park staff and by cleaning boats and equipment before transportation.

Other invasive plants, such as Chinese privet, are present in the forested areas along the Eno River.

The Hillsborough Stormwater and Environmental Services Division will hold a volunteer workday from 9 a.m. to noon Saturday, June 2.

The workday is part of a larger project to restore the habitat along the Eno River, reduce storm water runoff pollution and improve the river’s water quality.

The project is a partnership between the Piedmont Conservation Council and the town of Hillsborough.

Want to help

To participate in Saturday's workday, volunteers should gather at the Adron F. Thompson Water/Sewer Facility at 715 Dimmocks Mill Road in Hillsborough.

Participants will remove invasive plant species by hand in the forest. Tools will be provided, but participants are encouraged to bring work gloves and water.